This invention relates generally to drill feed mechanisms, and more particularly to drill rigs in which the drill bit is supported and positioned utilizing a chain.
Presently, drilling involves intermittent feed arrangements. In these systems, a length of drill pipe is connected between the top drive and the drill bit. As soon as the drill has drilled for the maximum stroke of the drill rig, then the top drive is disconnected from the drill pipe, and a new length of drill pipe is inserted between the top drive and the old drill pipe section. Whenever is is desired to raise the drill bit, then the reverse operation must be performed.
This operation is extremely labor intensive and monotonous since an operator is required to couple or uncouple each drill pipe section. Considering the depth drilled to in most circumstances, and the number of times it is required to raise and lower the drill bit or core member (as is common in core sampling), it is easy to understand how a considerable amount of drilling and labor time could be saved in most drilling operations.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.
In one aspect of the present invention, this is accomplished by providing a continuous feed system for a drill comprising a down-hole drill assembly having a support end and a drilling bit. Rotation is imported to the down-hole drill assembly between the support end and the drilling bit, which results in a torque being applied to the support end. A vertically disposed support chain has two ends, one end of the chain is connected to the support end. The chain resists the torque with limited torsional flexibility. A drive interacts with the chain at a point between the two ends for positively providing axial extension of a length of the chain